1. Field of the Invention
The invention relates to the field of methods for transferring alarm data between a broken-down railway vehicle and a control center, as well as devices for carrying out such methods.
When a train, or any other railway vehicle such as a subway, tramway or equivalent, breaks down on the middle of a track, the operator of that train wishes for a rapid and adapted intervention to minimize the impact of that breakdown in terms of penalties related to an untimely occupation of the track, costs due to inappropriate referral of the train to a maintenance workshop, disorganization of traffic, inconveniences caused to the passengers of the broken-down train and those of trains whereof the travel is disrupted, etc.
2. Brief Discussion of the Related Art
Trains today are equipped with maintenance means able to determine an operating state of the train from different parameters.
When a train breaks down, these maintenance means inform a fixed control center, on the ground, by transferring it alarm data. This alarm data includes at least one identifier of the train, an alarm signal and secondary data relative to the state of the broken-down train. This information allows the control center, by implementing expert data processing means, to try to diagnose the nature of the breakdown, develop an intervention strategy and mobilize the means adapted to perform that intervention.
The communication between a train and the control center is done through a ground communication infrastructure making it possible to establish a wireless connection. A train is equipped with communication means adapted to establish such a wireless connection. The wireless connection is established periodically, when the train is located within the coverage zone of the communication infrastructure on the ground. This coverage zone generally includes train stations, maintenance workshops, certain important points of the rail network, but does not cover all of the tracks that the trains in a fleet of trains may use.
However, a train can break down and be immobilized on the track at a point that does not belong to the coverage zone of the ground communication infrastructure. It is then impossible for the broken-down train to establish a communication link with the ground infrastructure, and, consequently, to inform the control center of the situation. The intervention chain is not triggered.
More generally, the fact that the broken-down train cannot establish a link with the ground infrastructure includes a number of situations: the broken-down train may be located outside the coverage zone of the ground communication infrastructure, and it is impossible to establish any wireless link whatsoever; the broken-down train can be located in the coverage zone of the ground communication infrastructure, but the quality of the link between the broken-down train and the ground infrastructure is greatly damaged because, for example, of a screening phenomenon due to electromagnetic disruptions or the presence of another train concealing a wireless access point in a tunnel; lastly, the breakdown that affects the train can in fact affect the wireless communication means normally used to establish a wireless link between the train and the ground infrastructure or the train's onboard computer, which implements the maintenance means.